He said Labour in the Scottish government worked in a coalition with the Lib Dems between 1999 and 2007.

“It seems to me that there is some times a risk of a conceit on the part of Labour members in thinking that Liberal Democrats are just Labour party members who got lost on the way to the committee rooms,” he said.

“We should respect the fact that they represent a distinctive tradition and that they have an instinct for self preservation which is common in all political parties.”

However, Mr Miliband attacked the Lib Dem leader describing the him as an embarrassment to Lib Dem members.

He told The Daily Telegraph: “I don’t know what to say about Nick Clegg, If I was a Lib Dem, I would be just tearing my hair out. He is .. a passenger on the George Osborne super tanker. I’d be embarrassed.”

Labour and the Conservatives have been neck-and-neck in most opinion polls over recent months. Some senior Labour figures believe that a hung parliament is the most likely outcome of the next election, which is due in 2015.